This invention relates to an improvement of an apparatus for cleaning windowpanes of a building and, more particularly, to an apparatus capable of wiping a windowpane of a multistoried building efficiently and safely by wiping off dust deposited on the windowpane while sprinkling water on the windowpane and collecting the wiped off dust.
For keeping windowpanes of a multistoried building clean, these windowpanes need to be cleaned regularly. A conventional method for cleaning windowpanes of a multistoried building relies on a hand work according to which a workman on a gondola suspended from the roof of the building sprinkles water on the windowpanes and then wipes off dust with a scraper. The conventional method however is apparently inefficient and dangerous.
For overcoming the defects of the conventional cleaning method, there has been proposed, as disclosed in Japanese Utility model Publication No. 58-22680, an apparatus for automatically cleaning windowpanes of a multistoried building. This apparatus comprises, as shown in FIG. 7, a cleaning unit 1 suspended from the roof of a building and being capable of ascending and descending along the outer wall of the building, a pair of vertically arranged scrapers 2 and 3 which are provided in the cleaning unit 1 so that they can abut against a windowpane and move forwardly and rearwardly and a sprinkling nozzle 4 provided between the scrapers 2 and 3. Water is sprinkled by the sprinkling nozzle 4 over the windowpane while the cleaning unit 1 is descending and soiled water containing dust is scraped off by the upper scraper 2 and is recovered by the lower scraper 3 into a soiled water tank (not shown).
The proposed apparatus however has the disadvantage that frictional resistance caused during descending of the cleaning unit 1 is very large since the cleaning unit 1 descends while the upper and lower scrapers 2 and 3 are in abutting engagement against the windowpane. Difficulty arises particularly when windowpanes of a wide range are to be cleaned all at once by a plurality of horizontally arranged cleaning apparatuses.
The prior art apparatus has also the problem that the sprinkling nozzle tends to b blocked with foreign matters mixed in sprinkling water or dust scraped off during cleaning with a result that the nozzle loses its water sprinkling function.
Further, in the prior art apparatus in which the cleaning unit 1 descends while the scrapers 2 and 3 are in abutting engagement with the windowpane, if moving of the scrapers 2 and 3 forwardly and rearwardly during cleaning is not made at a proper timing, there will remain an unwiped area in the windowpane.
If it is attempted to adjust the position of the cleaning unit 1 for preventing occurrence of the unwiped area, the position of the cleaning unit 1 which is heavy and wide must be finely adjusted with a result that a skill and complex control for such fine adjustment are required.
It is, therefore, an object of the invention to provide an apparatus for cleaning windowpanes capable of reducing frictional resistance relative to windowpanes and thereby smoothly cleaning the windowpanes.
It is another object of the invention to provide an apparatus for cleaning windowpanes capable of preventing blocking of a sprinkling element and attaining complete cleaning without occurrence of an unwiped area on the windowpanes.